Through-substrate vias are conventionally used to realize high-frequency and high-performance transistors and integrated circuits. A conventional die attachment method for such transistors and integrated circuits is to use a gold-silicon eutectic. The gold-silicon eutectic approach has a reduced variability over other methods, such as approaches employing gold-tin preforms. Although the gold-silicon eutectic approach works well, an introduction of the through-substrate vias has been found, in practice, to impose a limit on a range of temperatures and dwell/scrub times that can be utilized during the die attachments. At sufficient temperature and/or time, the front-side contact interfaces of the through-substrate vias can be breached by the gold-silicon eutectic alloy. Therefore, the front-side contact interfaces become compromised. The breaching is especially limiting with multi-die assemblies.
It would be desirable to implement a barrier for preventing eutectic break-through in through-substrate vias.